Lowering trough assembly for use with a continuous casting machine



CHINE 9, 1969 A. SZENTASZLOI ET LOWERING THOUGH ASSEMBLY FOR USE WITH CONTINUOUS CASTING MA Filed Feb. 10, 1967 a Sheets-Sheet 1 FIGFI INVENTORS- ALEXANDER SZENTASZLOI 8| MELVIN I. WEISS ATTORNEYS.

Aug. 19, 1969 A. SZENTASZLOI ET AL 3. 6 3 A LOWERING THOUGH ASSEMBLY FOR USE WITH A CONTINUOUS CASTING MACHINE Filed Feb. 10', 1967 v a sheet -sheet 2 INVENTORS.

ALEXANDER SZENTASZLOI 8| MELVIN I. WEISS BY ATTORN EYS Aug. 19,1969 A.szEN'rAszLO| 3 461 5 LOWERING THOUGH ASSEMBLY FOR USE WITH A CONTINUOUS CASTING MACHINE Filed Feb. 10, 1967 5 sheets-sheet s FIG. 4 I

50 5 N so INVENTORS.

5O ALEXANDER SZENTASZLOI 8 MELVIN I. WEISS ZZ 744M, a 304.,

ATTORNEYS United States Patent 3,461,951 LOWERING TROUGH ASSEMBLY FOR USE WITH A CONTINUOUS CASTING MACHINE Alexander Szentaszloi, West Chester, and Melvin I. Weiss,

Broomall, Pa., assignors to E. W. Bliss Company, Canton, Ohio, a corporation of Delaware Filed Feb. 10, 1967, Ser. No. 615,208 Int. Cl. B22d 11/12 US. Cl. 164-282 6 Claims ABSTRACT OF THE DISCLOSURE The present invention is directed toward the continuous casting art, and more particularly to an improved apparatus for handling the billets or slabs severed from the vertically extending casting coming from a vertical down casting continuous casting machine.

In continuous casting apparatus of the type referred to above, a vertically downwardly moving casting is continuously withdrawn from the open bottom end of a water cooled mold by withdrawal rolls. A cut-off torch assembly, the movement of which is coordinated with the movement of the casting, is provided to sever the vertically moving casting into billets or slabs of predetermined lengths determined by subsequent working or handling. In order to receive the slab or billet and lower it from its original vertical position to a horizontal position, an apparatus, commonly referred to as a lowering trough assembly is provided.

In general, most present lowering trough assemblies comprise a frame or cradle adapted to be moved from a vertical slab receiving position beneath the mold of th continuous casting machine, to a horizontal slab discharge position. The frame or cradle is provided with a support platform or stop which extends laterally from the side thereof to engage and support the lower end of a slab cut from the continuous casting. To permit the trough assembly to handle slabs of different lengths, the stop is manually adjustable longitudinally of the frame or cradle.

Apparatus, such as driven rolls or hoists, is provided to transfer the slab from the trough or cradle to a runout table or conveying apparatus after the slab has been moved to the lower horizontal position.

The above-described lowering trough apparatus has certain inherent shortcomings. For instance, whenever it is desired to vary the length of slab being cut, it is necessary to reposition the stop longitudinally of the cradle. Because of the large weight of the slabs normally being handled, these stops are relatively large and heavy. This makes manual repositioning diflicult and time consuming. Also, the additional apparatus required to move the lowered slab from the trough or cradle onto the runout table or conveying apparatus increases the cost of the system, as well as taking up space which could be otherwise utilized.

During start up of the continuous casting machine a dummy bar, which is a solid bar of metal, must be positioned in the open bottom of the chilled or cooled mold to block the exit of metal from the mold until it has reached the proper level and has solidified. The

"ice

dummy bar must then be withdrawn at a rate coordinated with the solidification of metal in the mold to permit the continuous casting to exit therefrom. Generally, the lowering trough structure and withdrawal rolls are utilized to perform this function. With prior trough struc- .tures it was necessary to very accurately position the dummy bar on the trough while the trough was in its lowered or horizontal position. The trough was then raised to its vertical position and moved vertically upward. This forced the dummy bar upwardly into engagement with the withdrawal rolls which were driven to push the dummy bar into position within the mold.

As can be seen, in order for the dummy bar to properly enter the mold opening, it must be positioned extremely accurately on the trough. Additionally, because the dummy bar is being gripped by the withdrawal rolls during its movement into the mold, it is extremely difficult to perform any realignment at this time. These factors tend to complicate and delay proper placement of the dummy bar within the mold.

The present invention provides a lowering trough assembly which is extremely simple in construction and operation, and which overcomes all the above disadvantages associated with prior flowering trough apparatus. Further, the present invention provides a method of dummy bar placement which greatly facilitates start-up of the continuous casting machine.

In accordance with the present invention an improved lowering trough assembly, of the general type described, is provided. The improvement to the assembly includes selectively operable drive means carried by the assembly and movable therewith, and means to interconnect the drive means with the previously-mentioned slab supporting stop member to selectively move the stop member longitudinally of the trough.

By providing the driven stop member the problems of adjusting the position of the stop on the trough are eliminated. Additionally, the driven stop member can be utilized to move the slab from the trough onto the associated roll-out table or conveying apparatus.

Additionally, the improved lowering trough permits of an improved method of dummy bar placement during start-up of the continuous casting machine. This method includes placing the dummy bar on the trough assembly while the trough assembly is in the horizontal position, and then moving both the trough assembly and the dummy bar to the vertical position. With the withdrawal rolls open and the trough and dummy bar in the vertical position, the stop member is driven to move the dummy bar toward the mold. As the dummy bar moves toward the mold, its alignment therewith is checked, and a transversely directed force is applied to properly align it.

Because the withdrawal rolls are open during dummy bar placement, it is a relatively easy matter to perform any necessary alignment. This eliminates the need for positioning the dummy bar on the trough assembly with great accuracy and, thus, facilitates start-up of the casting machine.

A primary object of the present invention is to provide an improved lowering trough assembly having a power driven stop member.

A further object is the provision of a lowering trough assembly which eliminates the need for separate conveying or hoisting apparatus, for removing a cut slab from the lowering trough.

An additional object of the present invention is the provision of a lowering trough assembly which is simply constructed and overcomes problems inherent with prior lowering trough apparatus.

Another object of the present invention is the provision of a lowering trough assembly which can be used for dummy bar placement during start-up of the continuous casting machine.

These and other objects and advantages will become apparent from the following description used to illustrate a preferred embodiment of the present invention when read in conjunction with the accompanying drawings wherein:

FIGURE 1 is an elevational view of a lowering trough assembly constructed in accordance with the present invention;

FIGURE 2 is a side elevation of the slab receiving cradle or trough of the assembly of FIGURE 1;

FIGURE 3 is a plan view of the slab receiving trough or cradle showing in FIGURE 2;

FIGURE 4 is a cross-sectional view taken on line 44 of FIGURE 2; and I FIGURE 5 is a cross-sectional view taken on line 5-5 of FIGURE 2.

Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting same, FIGURE 1 shows the overall arrangement of lowering trough assembly A comprised of guide frame work B carrying a trough or cradle assembly C which is movable from a lower horizontal position (shown by solid lines) to any of a plurality of vertical positions (shown by dotted lines). In the vertical positions the cradle assembly functions to receive slabs cut by torch assembly D from the continuous casting 20 existing from a continuous casting machine (not shown). While in the lower position it functions to discharge the slab to a runout table or conveyor.

The specific arrangement of guide framework B is not important to the present invention, and any guiding arrangement capable of guiding the cradle between the required positions could be used. However, as shown, guide framework B is comprised of two pairs of vertically extending beams 10. Although only one pair of the beams is shown, a second pair is positioned a space distance directly behind the pair shown in FIGURE 1. The beams of each pair are spaced a short distance apart to define an open guideway 12. The beams are supported at their lower end by being mounted in a suitable foundation 14 and are supported at their upper end in any convenient manner, such as by being bolted or welded to the building framework members 16.

A second pair of similarly spaced open guideways 19 are formed by two pairs of beam members 18 which are supported from building framework members 16.

As shown, the guide framework is positioned so that when the trough or cradle C is moved to its vertical position, as shown in dotted lines and indicated generally by the reference number 78, it will be in the proper location to receive the continuous casting 20 which is being withdrawn from a vertical down casting machine (not shown) by driven withdraw rolls 22 which are movable between casting engaging and non-engaging positions.

A cut-01f torch assembly D is provided to sever the required length of slab from the moving continuous casting 20. The actual arrangement of cut-off torch assembly D forms no part of the present invention and could, for example, be constructed in the manner shown in US. Patent 2,582,329. Any torch assembly capable of moving a cutting torch vertically downward at a speed corresponding to the speed of the casting 20 while simultaneously causing the torch to traverse the width of the casting could be utilized. As shown, torch assembly D comprises a main support frame 30 which carries a conventional cut-off torch 32. In order to provide the necessary vertical component of motion frame 30 is supported from a pair of cables 34 which extend upwardly over pulleys or sheaves 36 to a counterweight not shown. In order to cause the frame 30 to move downwardly at a speed corresponding to the speed of the casting a clamp mechanism 37 is provided to grip the casting and allow the downward movement of the casting to pull or force the frame 30 and the torch assembly vertically downward at the same speed as the casting. Means (not shown) are also provided to cause the torch 32 to move transverse to frame 30 during this vertical downward movement to thereby traverse the casting and severe the slab 21 therefrom. After the slab 21 has been severed, the clamp mechanism 37 is released in any convenient manner, and the counterweight acts to pull the frame 30 and the torch to their upper position preparatory to cutting another slab.

The slab severed by torch assembly D is received by the trough or cradle assembly C which at this time is in the position shown by dotted lines and identified generally by reference numeral 78. The lower end of the slab contacts a shelf or stop member carried by the cradle and indicated by the numeral 80. The portion of the cradle immediately above stop provides a vertically extending slab receiving surface formed in a manner subsequently to be described.

In order to guide the slab into position on the stop and the slab receiving surface a plurality of transversely spaced, downwardly extending guide bars 39 are carried by the left vertical guideway forming beams 10. Additionally, a pivotally mounted pressure bar which is actuated against the side of the slab to hold it against the cradle or trough is also provided. This pressure bar comprises a pivotally mounted lever 38 which is moved in a counterclockwise direction against the slab by a double acting air cylinder 40 carried by support 42 which extends downwardly from building support steel 16.

As best shown in FIGURES 2 and 3, trough assembly C includes a main frame comprised of a pair of spaced parallelly extending beams 50 which are connected by a plurality of transversely extending beams 52 bolted or welded to beams 50. A pair of vertically extending beams 54 are connected to the left end of beams 50 and are connected at their upper ends to a second pair of beam members formed by channels 56. The previously mentioned slab receiving surface of the cradle is formed by a plurality of transversely extending roller members 60 which are carried by pillow blocks or bearings 62 connected to the top surface of beams 50.

The means used to guide the cradle as it is moved between its horizontal and vertical positions comprise two pairs of guide rollers 63 and 64 which are positioned on opposite sides of the cradle for engagement with guideways 12 and 19 respectively, of guide frame work B. Guide rollers 64 are rotatably mounted on a shaft 70 which extends transversely through beams 50, while guide rollers 63 are carried on a rotatable shaft 66 which is carried by pillow blocks 68 mounted on the vertically extending frame members 56.

The means used to move the cradle assembly C between its lower horizontal position and its vertical position comprise sheaves rotatably mounted on the outer ends of shaft 70. As shown in FIGURE 1, these sheaves are adapted to be engaged by cables 74 which are fixed to the top of right hand frame members 10 and passed down- Wardly around sheaves 72 and thence back up to an upper drum or sheave 76 and across to a hoist or lifting mechanism not shown. Any convenient type of lifting mechanism could be utilized, such as an electrically driven drum hoist of the type shown in US. Patent 2,582,329.

As can be seen, by winding in cable 74 the cradle is caused to move upwardly and simultaneously swing counterclockwise from its lower horizontal position to its vertical position because of the arrangement of the guideways 19 and 12.

With the cradle in the vertical position, stop member 80 and the slab receiving surface defined by rollers 60 cooperate to receive and hold the cut slab. As shown in FIGURE 1, the stop 80 is normally positioned so that when the slab 21 is completely cut from the continuous casting its lower end is at a position slightly thereabove.

As best shown in FIGURES 2 and B the portion of the stop 80 which receives the end of the slab is comprised of a generally U-shaped frame 84 having a slab end receiving surface 81 which extends substantially entirely across the width of the cradle and generally perpendicular thereto. Attached to the top of frame 84 and extending longitudinally of the cradle are a plurality of guide fingers 85 which serve to assist in guiding the slab into position on the surface 81.

As can readily be seen, the longitudinal position of stop 80 relative to the cradle is dictated by the length of slab being out. For this reason, the stops position must be capable of being adjusted. As previously mentioned, in the past this repositioning or adjustment has been done manually. However, because of the weight of the slabs which must be handled, the stop itself must be large and heavy. Consequently, manual repositioning is difficult and time consuming.

The present invention overcomes problems previously encountered and provides a unique arrangement which allows the stop to be repositioned automatically. Additionally, the mechanism provided permits the stop to perform functions which previously required additional mechanism.

As best shown in FIGURES 2 through 5, the means for permitting stop 80 to be automatically repositioned include a pair of guideway forming rail members 82 mounted longitudinally of the trough or cradle on beams 50. The U-shaped frame 84 is provided with four Wheels or rollers 86 which cooperate with rail members 82 for guided movement therealong.

The means for maintaining the wheels 86 of the stop 80 in contact with the rails 82 and moving it to its desired location longitudinally thereof comprise a pair of high strength chains 90 which are connected to opposite lateral sides of the frame 84 and pass over sprockets 92 carried at the right hand or front end of the frame by a shaft 94 mounted in bearings or pillow blocks 96 fixed to the top of beams 50. Pillow blocks 96 are preferably provided with an adjusting mechanism so as to permit the chains to be tightened. As best shown in FIGURE 2, the chains pass over the sprockets 92 and back along the side of the trough into engagement with a second pair of sprockets 98 which are carried on a shaft 100 mounted in bearing blocks 104 afiixed to the left end of beams 50. The chains then pass up and into connection with the left side of stop frame 84. Preferably, heat shields would be provided to protect chains 90 from the intense heat of the casting.

The means for driving chains 90 to move the stop to its desired position could take a variety of forms, however, as shown in the preferred embodiment, it includes a conventional self-locking gear reducer 102 which is driven by a conventional variable speed reversible electric motor 106. The output shaft of motor 106 is connected through a coupling 108 with the transversely extending input shaft 110 of the gear reducer.

The self-locking feature of the gear reducer unit serves to prevent movement of the stop except in response to rotation of motor 106. However, as an additional safety feature the input shaft 110 extends completely through the gear reducer unit and is connected at its right hand end through a coupling 112 to a brake 114 which is mounted on the vertically extending frame beam 54. Consequently, when the stop has been moved to its desired position for receiving the slab, the combined self-locking feature of the gear reducer plus the actuation of brake 114 prevent any movement of the stop.

A variety of control mechanisms and arrangements, either manual or automatic, could be provided to control the energization of motor 106. For example, adjustable limit switches could be provided for engagement by stop frame 84 to cause de-energization of the motor 106 at the desired position of the stop. The actual type of controls utilized are not of importance to the invention.

In addition to eliminating the problems attendant with manual stop positioning arrangements as used in the prior art, the present arrangement eliminates the need for hoisting or transferring mechanism for moving the slab from the trough when the trough has been lowered to the hori- Zontal position. As best shown in FIGURE 1, simply by actuating the motor 106 to drive stop to the right, the slab 21 is driven onto the run-out table 23 Where it can subsequently be conveyed to storage or facilities for further treatment.

Further, the above described structure facilitates the start-up of each run of the continuous casting machine. As previously mentioned, on start-up a section of casting or dummy bar must be inserted into the mold of the continuous casting machine. Molten metal is then delivered to the mold and when the metal in the mold has reached a predetermined level the dummy bar is withdrawn at a rate coordinated with the delivery of molten metal to the mold and solidification therein.

In the past it has been necessary to manually position the stop on the trough at a location which would permit a portion of the dummy bar to extend beyond the end of the trough. The dummy bar was then very accurately positioned transversely of the trough, and the trough rotated to its vertical position. Following this, the dummy bar was moved vertically upward to the withdrawal rolls by moving the trough to its highest vertical position shown by dotted lines in FIGURE 1. Reverse operation of the withdrawal rolls then served to drive the dummy bar upwardly into the mold.

Unless the bar were positioned extremely accurately transversely of the trough, misalignment with the mold occurred. Because the bar was being gripped by the withdrawal rolls, this misalignment could not be easily corrected.

The previously described structure can, of course, be used in the conventional manner for dummy bar placement, additionally however, it does permit use of a method of placement of the dummy bar which overcomes the above misalignment problems and greatly facilitates start-up of the continuous casting machine. This method comprises utilizing the above described structure in generally the following manner:

First, with the trough assembly in its horizontal position, the stop 80 is driven to its right hand position as shown by dotted lines in FIGURE 2. The end of the dummy bar, or the end section thereof, is then pinned, clamped or otherwise rele-asably connected to the stop and the stop driven to the left end of the trough to move the dummy bar roughly into position on the trough.

Secondly, the dummy bar is disconnected from the stop and the dummy bar and trough assembly rotated to the vertical position.

Thirdly, the withdrawal rolls have been opened (either prior to movement of the trough to vertical, or during or immediately thereafter), and the stop drive is actuated to move the dummy bar vertically upward toward position in the mold.

Fourthly, as the dummy bar is moved toward the mold the transverse positioning of the bar relative the mold is checked and final alignment made by applying a transversely directed guiding force to the bar. Because the withdrawal rolls are opened, this final positioning is easily accomplished either by selectively actuated guide members, or fixedly positioned guides, such as rolls, mounted transversely to the withdrawal rolls and sub jacent the mold.

Finally, after the dummy bar is positioned in the mold, the withdrawal rolls are actuated into clamping position on the dummy bar. At this time the stop is driven to a lower position for receiving the end of the dummy bar as casting begins, or the trough is lowered for receipt and subsequent placement of a second dummy bar section if required.

As can readily be seen, the above described method eliminates the requirement that the dummy bar be originally located on the trough with extreme accuracy and, consequently, speeds up its placement.

The invention has been described in great detail sufficient to enable one skilled in the art to practice the invention. Obviously modifications and alterations of the preferred embodiment will occur to others upon a reading and understanding of this specification and it is our intention to include all such modifications and alterations as part of our invention insofar as they come within the scope of the appended claims.

Having thus described our invention, we claim:

1. In apparatus for handling severed lengths of a continuous casting comprising an elongated cradle having a frame and a longitudinally extending receiving surface, a stop member mounted on said frame and having a surface extending generally transversely to said receiving surface and adapted to cooperate therewith to support a severed casting thereon, means adapted to raise and lower said frame, and guide means arranged to direct the movement of said frame from a vertical casting receiving position to a horizontal discharging position, the improvement comprising: drive means carried on said frame and movable therewith, means for mounting said stop member for movement longitudinally of said frame and means interconnecting said drive means and said stop member for moving said stop member longitudinally of said frame in response to movement of said drive means.

2. The improvement as defined in claim 1 wherein said means for mounting said stop member comprise rollers.

3. The improvement as defined in claim 1 wherein said means for mounting said stop member comprise guide rails carried on said frame and cooperating rollers carried on said stop member.

4. The improvement as defined in claim 1 wherein said means for mounting said stop member comprises a guideway extending longitudinally of said frame.

5. The improvement as defined in claim 1 wherein said means interconnecting said stop member and said drive means comprise chains extending longitudinally of said frame.

6. The improvement as defined in claim 1 wherein said drive means include a variable speed reversible electric motor.

References Cited UNITED STATES PATENTS 2,582,329 1/1952 Harter et a1. 164-282 X 2,696,646 12/1954 Loewenstein 16482 2,806,263 9/1957 Hogan 164263 2,898,650 8/1959 Fredriksson et al. 164-263 X FOREIGN PATENTS 202,291 2/ 1959 Austria. 1,113,066 8/1961 Germany. 1,220,563 7/ 1966 Germany.

J. SPENCER OVERHOLSER, Primary Examiner R. SPENCER ANNEAR, Assistant Examiner 

